In a typical mobile communications environment, a user equipment (UE) device such as a mobile phone (also known as a cellular or cell phone), a laptop computer with wireless communications capability, or a personal digital assistant (PDA), etc., may communicate voice and/or data signals with one or more service networks. The wireless communications between the UE and the service networks may be in compliance with various wireless technologies. Long-term evolution (LTE), initiated by the third generation partnership project (3GPP), is now being regarded as a new radio interface and radio network architecture that provides a high data rate, low latency, packet optimization, and improved system capacity and coverage. An evolution of core network with non-radio access aspects, known as System Architecture Evolution (SAE), is also initiated by 3GPP in accompanying with LTE.
Evolved Packet System (EPS) is a purely IP based network, consisting of UEs, a LTE radio access network known as Evolved Universal Terrestrial Radio Access Network (E-UTRAN), and a SAE core network known as Evolved Packet Core (EPC). The EPS uses the concept of “EPS bearers” to route IP traffic from a gateway in external packet data networks to the UE. A bearer is an IP packet flow with a specific Quality of Service (QoS) between the gateway and the UE. The E-UTRAN is simply a network of plurality of evolved Node-Bs (eNBs), generating a flat architecture and there is no centralized intelligent controller. The eNBs are normally inter-connected via the X2-interface and towards the EPC by the S1-interface. The EPC includes a Mobility Management Entity (MME), a Home Subscriber Server (HSS), a serving gateway (SGW), and a packet data network gateway (PDN GW or PGW). The MME deals with the control plane. It handles the signalling related to mobility and security for E-UTRAN access. The MME is responsible for the tracking and the paging of UE in idle-mode. It is the termination point of the Non-Access Stratum (NAS). The MME handles bearer management and connection management. The HSS is a database that contains user-related and subscriber-related information. The HSS also provides support functions in mobility management, call and session setup, user authentication and access authorization. The Serving GW is the point of interconnect between the radio-side and the EPC, and it serves the UE by routing the incoming and outgoing IP packets. The PDN GW is the point of interconnect between the EPC and external IP networks called PDN (Packet Data Network), and it routes packets to and from the PDNs.
A long term evolution-advanced (LTE-A) system, as its name implies, is an evolution of the LTE system and has a similar network structure to the LTE system. In LTE-related systems, Proximity-based Service (ProSe) communication has been developed as a technology which allows UEs to communicate directly with each other in close proximity without transmitting/receiving data and/or control signals to the other via an eNB, which means a local or direct path can be used between the UEs. Therefore, in the 3GPP LTE spectrum, the operator can move the data path (i.e., user plane) off the access to core networks to direct links between the UEs. Please note that, the procedure for a UE registers for ProSe to the EPC is called ProSe UE registration or ProSe device registration, and the procedure for a ProSe application user registers to an application server is called ProSe application user registration, also called ProSe application registration or ProSe user registration in short.
When a user of the UE registers with an application server for a ProSe application, he/she is designated an application identifier (and one application is identified by an application identifier). Regarding ProSe user registration on the UEs, there are three cases to be considered, as shown in FIGS. 1A˜1C. It should be noted that a user of the UE, e.g., the owner of a mobile phone or a laptop, may install multiple ProSe applications on his/her ProSe-enabled UE. The user may have one or more registered user accounts, i.e., user identifiers (user IDs) for each application.
In Case 1 of FIG. 1A, two applications are running on a user equipment, UE1, managed/provided by different application servers, AppServer 1 and AppServer 2, and the user of UE1 may have two user IDs, User-1A and User-2A for the two applications, respectively registered with AppServer 1 and AppServer 2.
In Case 2 of FIG. 1B, only one application is running on UE1 and managed/provided by an application server, AppServer 1, and the user of UE1 has two user IDs, User-1A and User-1B for the same application, both registered with AppServer 1.
In Case 3 of FIG. 1C, the user has two user equipments, UE1 and UE2 (e.g., a mobile phone and a laptop) running the same application managed by AppServer 1, and the user has one user ID, User-1A registered with AppServer 1, for the same application running on both UE1 and UE2.
However, some problems may be encountered while EPS deals with device (UE) registration and user registration when applying ProSe. For example, how EPS recognizes a ProSe-enabled UE with a device identifier and one or more application-level user identifiers (such as User-1A and User-1B in FIGS. 1A-1C), how EPS manages these identifiers, how EPS uses a temporary identifier for the ProSe service operated on a ProSe-enabled UE, and so on, are indefinite. Therefore, a registration method for ProSe UE registration and ProSe user registration to solve these problems is required.